Long wire IC package fabrication method

ABSTRACT

A method of forming an encapsulated integrated circuit package includes forming a large number of traces spaced a significant distance from the integrated circuit. Intermediate bonding pads are formed between the integrated circuit and the traces. Bond pads of the integrated circuit are electrically connected to corresponding traces by corresponding long wires, which are intermediately bonded to the intermediate bonding pads. Since the long wires are intermediately bonded to intermediate bonding pads and extend along the surface of the substrate, the long wires are not susceptible to wire sweep during the encapsulation process used to form the package body.

BACKGROUND OF THE INVENTION

1. Filed of the Invention

The present invention relates generally to the packaging of electroniccomponents. More particularly, the present invention relates to a methodof fabricating an integrated circuit package.

2. Description of the Related Art

Trends in modern integrated circuitry are generally towards smaller sizeand higher density. This has resulted in the requirement to fit a largenumber of bond pads (I/O pads) in a relatively small area of theintegrated circuit, sometimes called the semiconductor chip.

To route electrical signals to and from the integrated circuit, the bondpads of the integrated circuit were electrically connected to traces ona substrate. However, since the traces were generally larger in size andpitch, i.e., spacing, than the bond pads, the number of traces whichcould be formed directly adjacent to the integrated circuit was limited.

One technique for overcoming the size and pitch limitations of thetraces was to form the traces at a significant distance from theintegrated circuit. However, this caused the length of the bond wiresextending between the bond pads of the integrated circuit and thecorresponding traces to be relatively long. Long bond wires wereparticularly problematic during the subsequent plastic encapsulationtransfer molding process where the integrated circuit, the bond wires,and the substrate were transfer molded into a plastic encapsulant toform the finished integrated circuit package.

More particularly, during the plastic encapsulation transfer moldingprocess, the plastic encapsulant was caused to flow around theintegrated circuit, the bond wires, and substrate. This flow of plasticencapsulant against the bond wires caused: (1) the bond wires to becomedisconnected from the bond pads of the integrated circuit or from thetraces; (2) caused the bond wires to break; and/or (3) caused the bondwires to move and short one another. This phenomena is called “wiresweep”.

In the event a plastic encapsulation injection molding process was used,wire sweep was even more problematic. Generally, the plastic encapsulantwas injected around the integrated circuit, the bond wires and thesubstrate at a higher pressure in a plastic encapsulation injectionmolding process than in a plastic encapsulation transfer moldingprocess. Due to this higher pressure, more force was exerted against thebond wires, which were susceptible to wire sweep.

To avoid wire sweep, the bond wires were supported by an intermediatesection between the bond pads of the integrated circuit and the traces.

Rostoker, U.S. Pat. No. 5,753,970, which is herein incorporated byreference in its entirety, teaches a lead support structure whichsupported a bond wire at a point along its length such that the bondwire was mechanically constrained and could not short to adjacent bondwires (see lead support structures 700a, 700b, 700c of FIGS. 9a, 9b, 9c,respectively, of Rostoker). However, providing and attaching such a leadsupport structure to the substrate was relatively labor-intensive andcomplex and thus significantly added to the cost of the integratedcircuit package.

Typically, each trace was aligned with the specific bond pad on theintegrated circuit to which the trace was to be connected. The bond padson the integrated circuit were connected to the traces in the same orderthat the bond pads were position on the integrated circuit. However, incertain instances, it was desirable to allow for cross-over connectionsbetween the bond pads and the traces. Generally, a cross-over connectionis a connection between a bond pad and a trace which is not directlyaligned with the bond pad.

Gow, 3rd et al., U.S. Pat. No. 5,168,368, which is herein incorporatedby reference in its entirety, teaches a bridge which was bonded to afirst set of fingers of a lead frame. The bridge was located between theintegrated circuit and a second set of fingers. To form a cross-overconnection, a bond wire extending between a bond pad and a finger of thesecond set of fingers was intermediately bonded to the bridge above thefirst set of fingers. In this manner, the bond wire was crossed overfingers of the first set of fingers. However, providing and attachingsuch a bridge was relatively labor-intensive and complex and thussignificantly added to the cost of the integrated circuit package.

Thus, in both Rostoker and Gow, 3rd et al., an intermediate bondingstructure was provided between the bond pads and traces (fingers) toreduce the unsupported length of the bond wires and thus avoid wiresweep. However, the intermediate bonding structures had to be fabricatedseparately and attached to the package during assembly which, as setforth above, was relatively labor-intensive and complex and thussignificantly added to the cost of integrated circuit package.

SUMMARY OF THE INVENTION

In accordance with the present invention, a plastic encapsulatedintegrated circuit package having a large number of traces is presented.To allow the required large number of traces to be formed, the tracesare spaced a significant distance from the integrated circuit. Bond padsof the integrated circuit are electrically connected to correspondingtraces by corresponding long wires. Of importance, the long wires arenot susceptible to wire sweep during the plastic encapsulation transfermolding process used to form the package body.

The long wires are intermediately bonded to intermediate bonding padsbetween the integrated circuit and the traces. Of importance, thedistance between the bond pads of the integrated circuit and theintermediate bonding pads is sufficiently small such that loopedportions of the long wires, which extend between the bond pads of theintegrated circuit and the intermediate bonding pads, are notsusceptible to wire sweep.

Of further importance, surface runner portions of the long wires, whichextend between the intermediate bonding pads and the traces, extendalong and contact the upper surface of the substrate and so are also notsusceptible to wire sweep. More particularly, during the plasticencapsulation transfer molding process, the plastic encapsulant flowsover the surface runner portions instead of around the surface runnerportions. This, in turn, causes the plastic encapsulant to exert muchless force on the surface runner portions than if the surface runnerportions were suspended above the upper surface of the substrate.

Since the surface runner portions have much less force exerted on themduring the plastic encapsulation transfer molding process, the surfacerunner portions can be formed of a greater length than conventionalsuspended bond wires.

Recall that in the prior art, the unsupported sections of the bond wiresextending between the bond pads and the traces were suspended above thesubstrate. During the plastic encapsulation transfer molding process,the plastic encapsulant flowed around these unsupported sections of bondwires, which were susceptible to wire sweep.

For this reason, each unsupported section of bond wire had to be nogreater than the maximum allowable wire bond length. Thus, even using anintermediate bonding structure of the prior art, the allowable distancebetween the bond pads and the traces was equal to approximate twice themaximum allowable wire bond length. However, the distance between thebond pads and the traces needs to be greater than twice the maximumallowable wire bond length in certain instances, for example, when alarge number of traces are required.

To increase the distance between the bond pads and the traces,additional intermediate bonding structures were provided. However, theseadditional intermediate bonding structures had to be fabricatedseparately and attached to the package during assembly which furtheradded to the cost of the integrated circuit package.

Advantageously, by essentially eliminating the susceptibility of thesurface runner portions to wire sweep, the distance between the bondpads and the traces can be much greater than twice the maximum allowablewire bond length. Thus, use of the long wires in accordance with thepresent invention is well suited for applications in which the tracesare at a significant distance from the bond pads, for example, when alarge number of the traces are required.

Advantageously, the intermediate bonding pads are formed during thenormal processing of the substrate, e.g., during the formation of thetraces. Since the intermediate bonding pads are formed during the normalprocessing of the substrate, there are no additional procedures ormaterials required for the intermediate bonding pads. Accordingly, thereis essentially no cost associated with the intermediate bonding pads.

Recall that in the prior art, an intermediate bonding structure wasprovided between the bond pads and traces (fingers) to reduce theunsupported length of the bond wires and thus avoid wire sweep. However,the intermediate bonding structures had to be fabricated separately andattached to the package during assembly, which was relativelylabor-intensive and complex, and thus significantly added to the cost ofthe integrated circuit package. Accordingly, the package in accordancewith the present invention is fabricated at a lower cost than anintegrated circuit package of the prior art.

In an alternative embodiment, a lower long wire electrically connects afirst bond pad to a first trace. An upper long wire electricallyconnects a second bond pad to a second trace. To make the electricalconnection between the second bond pad and the second trace, the upperlong wire has to cross over the lower long wire. To allow the upper longwire to cross over the lower long wire, a crossover portion of the upperlong wire is attached to a first jumper pad and a second jumper pad andextends over the lower long wire. In this manner, the upper long wirecrosses over the lower long wire.

Alternatively, to allow the upper long wire to cross over the lower longwire, a crossover portion of the upper long wire is a trace electricallyconnected to the first jumper pad and the second jumper pad. This traceextends under the lower long wire. In this manner, the upper long wireextends under the lower long wire to form a crossover connection overthe lower long wire.

Recall that in the prior art, a bridge was mounted above a first set offingers. To form a crossover connection, a bond wire was extendedbetween a bond pad and the bridge and was intermediately bonded to thebridge. The bond wire was then extended from the bridge to a finger of asecond set of fingers. In this manner, the bond wire was crossed overfingers of the first set of fingers. However, providing and attachingsuch a bridge was relatively labor-intensive and complex and thussignificantly added to the cost of the integrated circuit package.

Advantageously, the jumper pads in accordance with the present inventionare formed during the normal processing of the substrate, e.g., duringthe formation of the traces. Since the jumper pads are formed during thenormal processing of the substrate, there are no additional proceduresor materials required for the jumper pads. Accordingly, there isessentially no cost associated with the jumper pads or the crossoverconnection of the upper long wire over the lower long wire.

In one embodiment, a plastic encapsulated integrated circuit packageincludes a substrate having a first surface with a die attach area andan electrically conductive trace formed thereon. An intermediate bondingpad between the die attach area and the trace is also on the firstsurface of the substrate.

In another embodiment, a plastic encapsulated integrated circuit packageincludes a substrate having a first surface with a die attach area. Anelectronic component has a first surface attached to the die attacharea, the electronic component having a second surface. A first bond padand a second bond pad are on the second surface of the electroniccomponent. A first bond wire is electrically connected to the first bondpad. A first jumper pad and a second jumper pad are on the first surfaceof the substrate. A crossover portion extends between and electricallyconnects the first jumper pad and the second jumper pad. The crossoverportion forms a crossover connection with respect to the first bondwire.

Also in accordance with the present invention, a method includes forminga first trace and an intermediate bonding pad on a first surface of asubstrate. An electronic component is attached to the first surface ofthe substrate, the electronic component have a first bond pad thereon.The first bond pad is electrically connected to the first trace by afirst bond wire attached to the intermediate bonding pad.

These and other features and advantages of the present invention will bemore readily apparent from the detailed description set forth belowtaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a plastic encapsulated integratedcircuit package in accordance with the present invention.

FIG. 2 is a top plan view of a portion of a package in accordance withone embodiment of the present invention.

FIG. 3A is a cross-sectional view of the package along the line III—IIIof FIG. 2 in accordance with one embodiment of the present invention.

FIG. 3B is a cross-sectional view of a package along the line III—III ofFIG. 2 in accordance with an alternative embodiment of the presentinvention.

FIG. 3C is a cross-sectional view of a package along the line III—III ofFIG. 2 in accordance with yet another alternative embodiment of thepresent invention.

FIG. 4A is a cross-sectional view of the package of FIGS. 2 and 3Aduring fabrication in accordance with one embodiment of the presentinvention.

FIG. 4B is a cross-sectional view of the package of FIG. 4A at a laterstage of fabrication.

FIG. 5 is a cross-sectional view of the package of FIGS. 2 and 3A duringfabrication in accordance with another embodiment of the presentinvention.

FIG. 6 is a top plan view of a portion of a package in accordance withanother embodiment of the present invention.

FIG. 7 is a top plan view of a portion of a package having a crossoverconnection in accordance with yet another embodiment of the presentinvention.

FIG. 8A is a cross-section view of the package along the line VIII—VIIIof FIG. 7 in accordance with one embodiment of the present invention.

FIG. 8B is a cross-section view of the package along the line VIII—VIIIof FIG. 7 in accordance with another embodiment of the presentinvention.

In the following description, the same or similar elements are labeledwith the same or similar reference numbers.

DETAILED DESCRIPTION

In accordance with the present invention, a plastic encapsulatedintegrated circuit package 100 (FIG. 1) having a large number of traces108 is presented. To allow the required large number of traces 108 to beformed, traces 108 are spaced a significant distance DT from integratedcircuit 104. Bond pads 106 of integrated circuit 104 are electricallyconnected to corresponding traces 108 by corresponding long wires 110.Of importance, long wires 110 are not susceptible to wire sweep duringthe plastic encapsulation transfer molding process used to form packagebody 120.

Referring now to FIGS. 2 and 3A, long wires 110 are intermediatelybonded to intermediate bonding pads 112 laterally between integratedcircuit 104 and traces 108. Of importance, the distance between bondpads 106 and intermediate bonding pads 112 is sufficiently small suchthat looped portions 208 of long wires 110, which extend between bondpads 106 and intermediate bonding pads 112, are not susceptible to wiresweep.

Of further importance, surface runner portions 210 of long wires 110,which extend between intermediate bonding pads 112 and traces 108,extend along and contact upper surface 102U of substrate 102 and so arealso not susceptible to wire sweep. More particularly, during theplastic encapsulation transfer molding process, the plastic encapsulantflows over surface runner portions 210 instead of around surface runnerportions 210. This, in turn, causes the plastic encapsulant to exertmuch less force on surface runner portions 210 than if surface runnerportions 210 were suspended above upper surface 102U.

Since surface runner portions 210 have much less force exerted on themduring the plastic encapsulation transfer molding process, surfacerunner portions 210 can be formed of a greater length than conventionalsuspended bond wires.

Recall that in the prior art, the unsupported sections of the bond wiresextending between the bond pads and the traces were suspended above thesubstrate. During the plastic encapsulation transfer molding process,the plastic encapsulant flowed around these unsupported sections of bondwires, which were susceptible to wire sweep.

For this reason, each unsupported section of bond wire had to be nogreater than the maximum allowable wire bond length. Thus, even using anintermediate bonding structure of the prior art, the allowable distancebetween the bond pads and the traces was equal to approximate twice themaximum allowable wire bond length. However, the distance between thebond pads and the traces needs to be greater than twice the maximumallowable wire bond length in certain instances, for example, when alarge number of traces are required.

To increase the distance between the bond pads and the traces,additional intermediate bonding structures were provided. However, theseadditional intermediate bonding structures had to be fabricatedseparately and attached to the package during assembly which furtheradded to the cost of the integrated circuit package.

Advantageously, by essentially eliminating the susceptibility of surfacerunner portions 210 to wire sweep, the distance between bond pads 106and traces 108 can be much greater than twice the maximum allowable wirebond length. Thus, use of long wires 110 is well suited for applicationsin which traces 108 are at a significant distance from bond pads 106,for example, when a large number of traces 108 are required.

Advantageously, intermediate bonding pads 112 are formed during thenormal processing of substrate 102A, e.g., during the formation oftraces 108. Since intermediate bonding pads 112 are formed during thenormal processing of substrate 102A, there are no additional proceduresor materials required for intermediate bonding pads 112. Accordingly,there is essentially no cost associated with intermediate bonding pads112.

Recall that in the prior art, an intermediate bonding structure wasprovided between the bond pads and traces (fingers) to reduce theunsupported length of the bond wires and thus avoid wire sweep. However,the intermediate bonding structures had to be fabricated separately andattached to the package during assembly, which was relativelylabor-intensive and complex, and thus significantly added to the cost ofthe integrated circuit package. Accordingly, package 100 in accordancewith the present invention is fabricated at a lower cost than anintegrated circuit package of the prior art.

Referring now to FIGS. 7 and 8A together, in an alternative embodiment,a lower long wire 110-2L electrically connects a bond pad 106B to atrace 108A. A crossover portion 704 of an upper long wire 110-2U isattached to a first jumper pad 702A and a second jumper pad 702B andextends over lower long wire 110-2L. Alternatively, crossover portion704A (FIG. 8B) is a trace extending under lower long wire 110-2L andelectrically connecting first jumper pad 702A to second jumper pad 702B.In this manner, upper long wire 110-2U crosses over lower long wire110-2L.

Recall that in the prior art, a bridge was mounted above a first set offingers. To form a crossover connection, a bond wire was extendedbetween a bond pad and the bridge and was intermediately bonded to thebridge. The bond wire was then extended from the bridge to a finger of asecond set of fingers. In this manner, the bond wire was crossed overfingers of the first set of fingers. However, providing and attachingsuch a bridge was relatively labor-intensive and complex and thussignificantly added to the cost of the integrated circuit package.

Advantageously, jumper pads 702A, 702B (and crossover portion 704A inthe FIG. 8B embodiment) are formed during the normal processing ofsubstrate 102A, e.g., during the formation of traces 108. Since jumperpads 702A, 702B are formed during the normal processing of substrate102A, there are no additional procedures or materials required forjumper pads 702A, 702B. Accordingly, there is essentially no costassociated with jumper pads 702A, 702B or the crossover connection ofupper long wire 110-2U over lower long wire 110-2L.

More particularly, FIG. 1 is a cross-sectional view of a plasticencapsulated integrated circuit package 100 in accordance with thepresent invention. Package 100 includes a substrate 102 having an upper,e.g., first, surface 102U. A lower, e.g., first, surface 104L of anintegrated circuit 104 is attached to a die attach area 107 of uppersurface 102U, for example, with adhesive. A plurality of bond pads 106are on an upper, e.g., second, surface 104U of integrated circuit 104.Although integrated circuit 104 is set forth, in light of thisdisclosure, it is understood that integrated circuit 104 can be replacedwith other electronic components.

Formed on upper surface 102U of substrate 102 are a plurality ofelectrically conductive traces 108. To allow the required large numberof traces 108 to be formed on upper surface 102U, traces 108 are spacedat a significant distance DT from integrated circuit 104, e.g., 0.50 to0.80 inches (12.7 to 20.3 millimeters). Illustratively, 64 to 200 traces108 are formed on upper surface 102U, traces 108 having a 100 micrometer(μm) width and a 100 μm spacing from one another, i.e., traces 108 havea 200 μm center to center pitch.

Bond pads 106 are electrically connected to corresponding traces 108 bybond wires 110 (hereinafter referred to as long wires 110). As discussedfurther below, long wires 110 extend from corresponding bond pads 106 tocorresponding intermediate bonding pads 112 on upper surface 102U ofsubstrate 102. Long wires 110 extend from intermediate bonding pads 112along upper surface 102U of substrate 102 to corresponding traces 108.

Traces 108 are electrically connected to corresponding traces 114 on alower, e.g., second, surface 102L of substrate 102 by correspondingelectrically conductive vias 116 extending through substrate 102. Formedon traces 114 are corresponding electrically conductive pads 115. Formedon pads 115 are corresponding electrically conductive interconnectionballs 118, e.g., solder balls. Interconnection balls 118 form theelectrical interconnections between package 100 and the larger substrate(not shown) such as a printed circuit mother board.

To illustrate, a first bond pad 106A of the plurality of bond pads 106is electrically connected to a first trace 108A of the plurality oftraces 108 by a first long wire 110A of the plurality of long wires 110.Trace 108A is electrically connected to a first trace 114A of theplurality of traces 114 by a first via 116A of the plurality of vias116. A first pad 115A of the plurality of pads 115 is formed on trace114A. A first interconnection ball 118A of the plurality ofinterconnection balls 118 is formed on first pad 115A. The other bondpads 106, long wires 110, traces 108, vias 116, traces 114, pads 115,and interconnection balls 118 are electrically connected to one anotherin a similar manner and so are not discussed further.

Although a particular electrically conductive pathway between bond pad106A and interconnection ball 118A is set forth, those of skill in theart will recognize that other electrically conductive pathways can beformed. For example, substrate 102 is a multi-layered laminate substrateand, instead of straight through vias 116, a plurality of electricallyconductive traces on various layers in substrate 102 are interconnectedby a plurality of electrically conductive vias to form the electricalinterconnections between traces 108 and 114. As a further example,interconnection balls 118 are distributed in an array format to form aball grid array (BGA) type package. Alternatively, interconnection balls118 are not formed, e.g., to form a metal land grid array (LGA) typepackage or a leadless chip carrier (LCC) type package. Otherelectrically conductive pathway modifications will be obvious to thoseof skill in the art.

Supported by and formed on upper surface 102U of substrate 102 is apackage body 120. Package body 120 is formed using a plasticencapsulation transfer or injection molding process wherein package 100is inserted into a mold and covered with plastic encapsulant, which istransferred (injected) into the mold. Alternatively, package body 120 isformed using a liquid encapsulation process wherein package 100 iscovered with a liquid encapsulant, which is cured. Plastic encapsulationtransfer molding processes, plastic encapsulation injection moldingprocesses and liquid encapsulation processes are well known to those ofskill in the art and are not discussed further to avoid detracting fromthe principals of the invention. For simplicity of discussion, a plasticencapsulation transfer molding process is hereinafter discussed,however, in light of this disclosure, it is understood that a plasticencapsulation injection molding process or a liquid encapsulationprocess could equally be used.

Package body 120 encloses integrated circuit 104, bond pads 106, longwires 110, intermediate bonding pads 112, and traces 108. Of importance,long wires 110 are not subject to wire sweep during the plasticencapsulation transfer molding process used to form package body 120 asdiscussed in greater detail below with reference to FIGS. 2 and 3A.

FIG. 2 is a top plan view of a portion 202 of a package 100A inaccordance with one embodiment of the present invention. FIG. 3A is across-sectional view of package 100A along the line III—III of FIG. 2 inaccordance with one embodiment of the present invention. In the figureswhich follow, package body 120 (FIG. 1) is not illustrated for purposesof clarity.

Referring to FIGS. 2 and 3A, in this embodiment, a substrate 102A is amulti-layer substrate, which includes a principal substrate 204 and anelectrically insulating layer 206 formed on principal substrate 204.Insulating layer 206 electrically isolates principal substrate 204including any electrically conductive structures of principal substrate204 from long wires 110.

Insulating layer 206 defines an upper surface 102U of substrate 102A.For example, principal substrate 204 is a printed circuit board orceramic type substrate and insulating layer 206 is a solder mask.Insulating layer 206 is formed on principal substrate 204 laterallybetween integrated circuit 104 and traces 108. However, in analternative embodiment, insulating layer 206 entirely covers principalsubstrate 204 and, in particular, extends underneath integrated circuit104 and traces 108. In yet another alternative embodiment, insulatinglayer 206 is not formed.

Formed on upper surface 102U of substrate 102A, and more particularly onor through insulating layer 206, are a plurality of intermediate bondingpads 112. Intermediate bonding pads 112 are formed adjacent to dieattach area 107 of upper surface 102U of substrate 102A and, moreparticularly, are formed on upper surface 102U of substrate 102Alaterally between die attach area 107 and traces 108.

Intermediate bonding pads 112 are formed of a material suitable forforming a wire bond connection thereto. For example, intermediatebonding pads 112 include a metal and, in one particular embodiment,intermediate bonding pads 112 are formed of the same metal or otherelectrically conductive material of which traces 108 are formed of. Ofimportance, before formation of long wires 110, intermediate bondingpads 112 are electrically isolated from one another and, more generally,from any electrically conductive structure of package 100. Statedanother way, intermediate bonding pads 112 are electrically floating.

Long wires 110 include first portions 208, hereinafter looped portions208, and second portions 210, hereinafter surface runner portions 210.Looped portions 208 extend between bond pads 106 and intermediatebonding pads 112. As an example, the distance between a bond pad 106 anda corresponding intermediate bonding pad 112 is in the range of 0.10 to0.20 inches (2.54 to 5.08 mm) and preferably is less than 0.050 inches(1.27 mm). Looped portions 208 are looped with an arc typical ofconventional wire bonds.

Surface runner portions 210 extend between intermediate bonding pads 112and traces 108. Surface runner portions 210 extend along and contactupper surface 102U.

As discussed in greater detail below with reference to FIGS. 4A and 4B,each long wire 110 includes a first wire, which forms looped portion208, and a second wire, which forms surface runner portion 210.Alternatively, as discussed in greater detail below with reference toFIG. 5, each long wire 110 is a single wire, which forms both loopedportion 208 and surface runner portion 210.

FIG. 4A is a cross-sectional view of package 100A of FIGS. 2 and 3Aduring fabrication in accordance with one embodiment of the presentinvention. Referring to FIG. 4A, to fabricate package 100A, substrate102A is formed. To illustrate, insulating layer 206 is formed onprincipal substrate 204 in a conventional manner. Traces 108 andintermediate bonding pads 112 are formed on substrate 102A. For example,intermediate bonding pads 112 are formed at the same time and during thesame processing used to form traces 108. Generally, an electricallyconductive layer is formed and selectively patterned, or, anelectrically conductive layer is selectively formed, to formintermediate bonding pads 112 and traces 108, as those of skill in theart will understand.

To illustrate, the electrically conductive layer is formed by plating orscreening an electrically conductive material on principal substrate204. As an example, principal substrate 204 is a printed circuit boardtype substrate and traces 108/intermediate bonding pads 112 aremultilayered metallizations such as: (1) copper; (2) nickel on thecopper; and (3) gold on the nickel. As an alternative example, principalsubstrate 204 is a ceramic type substrate and traces 108/intermediatebonding pads 112 are: (1) tungsten; (2) nickel on the tungsten; and (3)gold on the nickel.

Advantageously, intermediate bonding pads 112 are formed during thenormal processing of substrate 102A, e.g., during the formation oftraces 108. Since intermediate bonding pads 112 are formed during thenormal processing of substrate 102A, there are no additional proceduresor materials required for intermediate bonding pads 112. Accordingly,there is essentially no cost associated with intermediate bonding pads112.

Recall that in the prior art, an intermediate bonding structure wasprovided between the bond pads and traces (fingers) to reduce theunsupported length of the bond wires and thus avoid wire sweep. However,the intermediate bonding structures had to be fabricated separately andattached to the package during assembly, which was relativelylabor-intensive and complex, and thus significantly added to the cost ofthe integrated circuit package. Accordingly, package 100 in accordancewith the present invention is fabricated at a lower cost than anintegrated circuit package of the prior art.

After substrate 102A, traces 108, and intermediate bonding pads 112 arefabricated, integrated circuit 104 is attached to substrate 102A in aconventional manner such as with adhesive.

Bond pads 106 are wire bonded to traces 108 by long wires 110. To formeach long wire 110, a conventional wire bonder 410 bonds a first wire402 to a bond pad 106. An example of a suitable wirebonder 410 includesa KNS-1488 Turbo wirebonder manufactured by Kulick & Soffa Industries,Inc., 2101 Blair Mill Road, Willow Grove, Pa. 19090. In one embodiment,a gold or aluminum wire having a diameter in the approximate range of0.001 inches (0.025 mm) to 0.0013 inches (0.033 mm) is used. First wire402 is bonded to bond pad 106 and is stretched, i.e., extended from bondpad 106 to intermediate bonding pad 112 to form looped portion 208 oflong wire 110. First wire 402 is attached to intermediate bonding pad112 using a conventional wire bonding technique such as an ultrasonic orthermosonic bonding technique.

First wire 402 is terminated, i.e., cut, at intermediate bonding pad112. FIG. 4B is a cross-sectional view of package 100A of FIG. 4A at alater stage of fabrication. Referring now to FIG. 4B, a new second wire404 is attached to intermediate bonding pad 112. Preferable, second wire404 is attached to intermediate bonding pad 112 directly on top of firstwire 402 as illustrated in FIG. 4B. In this manner, the bond betweenlooped portion 208 of long wire 110 and intermediate bonding pad 112 isreinforced.

Second wire 404 is stretched flat along upper surface 102U of substrate102A to trace 108 to form surface runner portion 210 of long wire 110.Second wire 404 is bonded to trace 108 using a conventional wire bondingtechnique.

However, in an alternative embodiment, a single wire forms both loopedportion 208 and surface runner portion 210 of long wire 110, i.e., longwire is integral and, more particularly, is a single wire and not aplurality of separate wires connected together. FIG. 5 is across-sectional view of package 100A of FIGS. 2 and 3A duringfabrication in accordance with this alternative embodiment of thepresent invention. In this embodiment, a wire 502 is bonded to a bondpad 106 and is stretched to intermediate bonding pad 112. Wire 502 isstitched to intermediate bonding pad 112 by wire bonder 410. Generally,stitching involves bonding wire 502 to intermediate bonding pad 112without cutting wire 502.

Wire 502 is stretched flat along upper surface 102U of substrate 102Afrom intermediate bonding pad 112 to trace 108 to form surface runnerportion 210 of long wire 110. More particularly, wire 502 is stretchedflat along insulating layer 206. Wire 502 is then bonded to andterminated at trace 108 using a conventional wire bonding technique.

Advantageously, long wires 110 are formed using standard packagingequipment, i.e., standard wire bonders such as wire bonder 410 of FIGS.4A, 4B and 5. By using standard packaging equipment, large tooling,capital equipment, and training costs, which would otherwise be incurredwith nonstandard packaging equipment, are avoided.

In some instances, minor modifications to the standard wire bonder maybe necessary. For example, wire bonder software may have to be modifiedto allow stitching (instead of termination) of wires 502 (FIG. 5) tointermediate bonding pads 112, and to form surface runner portions 210of long wires 110 so that they lay flat on upper surface 102U ofsubstrate 102A (instead of being looped). However, such modificationsare minor and it is well within the skill of those skilled in the art ofwire bonding to make such modifications.

To finalize assembly of package 100A, referring again to FIGS. 2 and 3A,package 100A is encapsulated in plastic encapsulant to form package body120 using a conventional encapsulation process. (Package body 120 isillustrated in FIG. 1). More particularly, integrated circuit 104, bondpads 106, long wires 110, intermediate bonding pads 112, and traces 108are encapsulated in plastic encapsulant to form packing body 110.

Of importance, the distance between bond pads 106 and intermediatebonding pads 112 is sufficiently small such that looped portions 208 arenot susceptible to wire sweep during the plastic encapsulation transfermolding process. For example, the distance between bond pads 106 andintermediate bonding pads 112 is less than 0.20 inches (5.08millimeters) and, in one particular embodiment, is within the range of0.10 inches (2.54 millimeters) to 0.20 inches (5.08 millimeters) andpreferably is 0.050 inches (1.27 mm) or less.

Further, since surface runner portions 210 extend along upper surface102U, surface runner portions 210 are not susceptible to wire sweep.More particularly, during the plastic encapsulation transfer moldingprocess, the plastic encapsulant flows over surface runner portions 210instead of around surface runner portions 210. This, in turn, causes theplastic encapsulant to exert much less force on surface runner portions210 than if surface runner portions 210 were suspended above uppersurface 102U.

Since surface runner portions 210 have much less force exerted on themduring the plastic encapsulation transfer molding process, surfacerunner portions 210 can be formed of a greater length than conventionalsuspended bond wires. For example, the length of surface runner portions210, i.e., the distance between intermediate bonding pads 112 and traces108, is as great as 0.70 inches (17.78 millimeters) and, in oneembodiment, is within the approximate range of 0.50 inches to 0.70inches (12.70 millimeters to 17.78 millimeters) although surface runnerportions 210 are formed to have other lengths in other embodiments.

Recall that in the prior art, the unsupported sections of the bond wiresextending between the bond pads and the traces were suspended above thesubstrate. During the plastic encapsulation transfer molding process,the plastic encapsulant flowed around these unsupported sections of bondwires, which were susceptible to wire sweep.

For this reason, each unsupported section of bond wire had to be nogreater than the maximum allowable wire bond length, e.g., had to beless than or equal to 0.25 inches (6.35 millimeters) and preferably0.050 inches (1.27 mm) or less. Thus, even using an intermediate bondingstructure of the prior art, the allowable distance between the bond padsand the traces was equal to approximate twice the maximum allowable wirebond length. However, the distance between the bond pads and the tracesneeds to be greater than twice the maximum allowable wire bond length incertain instances, for example, when a large number of traces arerequired.

To increase the distance between the bond pads and the traces,additional intermediate bonding structures were provided. However, theseadditional intermediate bonding structures had to be fabricatedseparately and attached to the package during assembly which furtheradded to the cost of the integrated circuit package.

Advantageously, by essentially eliminating the susceptibility of surfacerunner portions 210 to wire sweep, the distance between bond pads 106and traces 108 can be much greater than twice the maximum allowable wirebond length. Further, this long distance between bond pads 106 andtraces 108 is realized without expending additional labor and/or addingcomplexity to the fabrication process. Thus, use of long wires 110 iswell suited for applications in which traces 108 are at a significantdistance from bond pads 106, for example, when a large number traces 108are required.

When the length of surface runner portion 210 of long wire 110 becomesextremely long, e.g., 0.300 inches (7.60 millimeters) or greater, it maybe advisable to attach surface runner portion 210 to upper surface 102Uof substrate 102A. FIG. 3B is a cross-sectional view of a package 100Balong the line III—III of FIG. 2 illustrating the anchoring of surfacerunner portion 210 to upper surface 102U in accordance with analternative embodiment of the present invention.

Referring to FIGS. 2 and 3B together, after long wires 110 are formedand before plastic encapsulation, beads 300 of adhesive (hereinafteradhesive beads 300) such as epoxy are dispensed over surface runnerportions 210 of long wires 110. (Adhesive beads 300 are illustrated indashed lines in FIG. 2 for purposes of clarity.) For example, Hysol 4323is dispensed to form adhesive beads 300 using an adhesive dispensingmachine such as a Camelot 5000 dispensing machine from Camelot Systems,Inc. of Massachusetts. Any one of a number of adhesive dispensingmachines can be used and the particular adhesive dispensing machine usedis not essential to the invention. After dispensing, adhesive beads 300are cured in a conventional manner.

Generally, at least one adhesive bead 300 is formed, e.g., two adhesivebeads 300 are formed. In one embodiment, height H of each adhesive bead300 above upper surface 102U of substrate 102A is within the approximaterange of 0.005 inches (0.127 millimeters) to 0.010 inches (0.254millimeters) and width W of each adhesive bead 300 is within theapproximate range of 0.010 inches (0.254 millimeters) to 0.020 inches(0.508 millimeters).

Surface runner portions 210 of long wires 110 extend through and areattached to adhesive beads 300. Adhesive beads 300 are also attached toupper surface 102U of substrate 102A. In this manner, surface runnerportions 210 are attached to, sometimes called anchored, to uppersurface 102U of substrate 102A. By anchoring surface runner portions 210to upper surface 102U of substrate 102A, any possibility of wire sweepof surface runner portions 210 is eliminated.

To finalize assembly of package 100B, package 100B is encapsulated inplastic encapsulant to form package body 120 using a conventionalplastic encapsulation transfer molding process. (Package body 120 isillustrated in FIG. 1).

FIG. 3C is a cross-sectional view of a package 100C along the lineIII—III of FIG. 2 illustrating the anchoring of surface runner portions210 to upper surface 102U in accordance with yet another alternativeembodiment of the present invention. In this embodiment, after longwires 110 are formed and before plastic encapsulation, a sealing layer320 is applied over surface runner portions 210 of long wires 110. Inone embodiment, sealing layer 320 is any one of the number ofconventional epoxy underfills, for example is Nagase 3002 epoxyunderfill of Shinetsu 5123 epoxy underfill. After application, sealinglayer 320 is cured.

In one embodiment, sealing layer 320 completely encloses surface runnerportions 210 of long wires 110 and intermediate bonding pads 112. Byencasing surface runner portions 210 within sealing layer 320, anypossibility of wire sweep of surface runner portions 210 is eliminated.To finalize assembly of package 100C, package 100C is encapsulated inplastic encapsulant to form package body 120 using a conventionalencapsulation process. (Package body 120 is illustrated in FIG. 1.)

FIG. 6 is a top plan view of a portion 602 of a package 100D inaccordance with another embodiment of the present invention. Package100D of FIG. 6 is substantially similar to package 100A of FIG. 3A andonly the relevant differences between packages 100D and 100A arediscussed below.

Referring to FIG. 6, in this embodiment, bond pads 106-1 are staggered,i.e., are not formed directly side by side. By staggering bond pads106-1, the number of bond pads 106-1 which can be formed within any unitlength along a side 104S of integrated circuit 104A is increasedcompared to having bond pads directly side by side (see bond pads 106 ofFIG. 2 for an example of a side-by-side arrangement of bond pads).Stated another way, by staggering bond pads 106-1, the pitch of bondpads 106-1 is minimized.

Advantageously, since long wires 110 are not susceptible to wire sweep,long wires 110 are well suited for use with extremely small pitch, e.g.,0.002 inches (0.050 mm), bond pads such as bond pads 106-1. Toillustrate, in one particular embodiment, long wires 110 have a diameterof 25 micrometers (μm) and are spaced apart from one another by 36 μm tohave a center to center pitch of 61 μm. To avoid interference, e.g.,parasitic capacitance, between long wires 110 when the pitch becomesrelatively small, intermediate bonding pads 112 are staggered as shownin FIG. 6.

FIG. 7 is a top plan view of a portion 701 of a package 100E having acrossover connection in accordance with one embodiment of the presentinvention. FIG. 8A is a cross-section view along the line VIII—VIII ofFIG. 7. Referring to FIGS. 7 and 8A together, a first long wire 110-2U(hereinafter upper long wire 110-2U) of a plurality of long wires 110-2crosses over a second long wire 110-2L (hereinafter lower long wire110-2L) of the plurality of long wires 110-2.

Lower long wire 110-2L includes a looped portion 208A and a surfacerunner portion 210A. Lower long wire 110-2L is formed in a mannersimilar to that described above with reference to long wires 110, e.g.,see FIGS. 4A, 4B and 5. More particularly, lower long wire 110-2Lextends from a first bond pad 106B of the plurality of bond pads 106 toan intermediate bonding pad 112A of the plurality of intermediatebonding pads 112. Lower long wire 110-2L extends from intermediatebonding pads 112A along upper surface 102U of substrate 102A to a firsttrace 108A of the plurality of traces 108.

Formed on upper surface 102U of substrate 102A is a first jumper pad702A and a second jumper pad 702B (collectively jumper pads 702).Illustratively, jumper pads 702 are formed at the same time, and duringthe same process, that intermediate bonding pads 112 are formed.Further, jumper pads 702 are essentially the same, or are the same, asintermediate bonding pads 112.

After lower long wire 110-2L is formed, upper long wire 110-2U isformed. Upper long wire 110-2U extends from a second bond pad 106C ofthe plurality of bond pads 106 to first jumper pad 702A. Upper long wire110-2U extends from first jumper pad 702A to second jumper pad 702B overlower long wire 110-2L. Upper long wire 110-2U extends from secondjumper pad 702B along upper surface 102U of substrate 102A to a secondtrace 108B of the plurality of traces 108.

To form upper long wire 110-2U, a conventional wire bonder bonds a firstwire to bond pad 106C. The first wire is stretched in a loop from bondpad 106C to jumper pad 702A to form a looped portion 208B of upper longwire 110-2U in a manner similar to that illustrated in FIG. 4A. Thefirst wire is attached to jumper pad 702A.

The first wire is then terminated at jumper pad 702A. A new second wireis then attached to jumper pad 702A. Preferable, this second wire isattached to jumper pad 702A directly on top of looped portion 208B ofupper long wire 110-2U in a manner similar to that illustrated in FIG.4B. This reinforces the bond between looped portion 208B of upper longwire 110-2U and jumper pad 702A.

The second wire is stretched in a loop from jumper pad 702A to jumperpad 702B to form a crossover portion 704 of upper long wire 110-2U. Thesecond wire is bonded to and terminated at jumper pad 702B.

As shown in FIG. 8A, crossover portion 704 is looped, sometimes calledarched, over surface runner portion 210A of lower long wire 110-2L. Ofimportance, the distance between jumper pad 702A and jumper pad 702B isno greater than the maximum allowable distance for a wire bond.Consequently, crossover portion 704 is not susceptible to wire sweep andthere is essentially no possibility that crossover portion 704 will comeinto contact with lower long wire 110-2L.

A new third wire is then attached to jumper pad 702B. Preferable, thisthird wire is attached to jumper pad 702B directly on top of crossoverportion 704 in a manner similar to that illustrated in FIG. 4B. Thisreinforces the bond between crossover portion 704 of upper long wire110-2U and jumper pad 702B.

The third wire is then stretched flat along upper surface 102U ofsubstrate 102A to trace 108B to form surface runner portion 210B ofupper long wire 110-2U. The third wire is bonded to and terminated attrace 108B. Since surface runner portion 210B of upper long wire 110-2Uextends along upper surface 102U, surface runner portion 210B is notsusceptible to wire sweep. Accordingly, surface runner portion 210B canbe formed of a greater length than conventional suspended bond wires.

In an alternative embodiment, instead of terminating the first wire atjumper pad 702A and terminating the second wire at jumper pad 702B andstretching a third wire between jumper pad 702B and trace 108 asdescribed above, the first wire is stitched to jumper pad 702A and isstitched to jumper pad 702B in a manner similar to that illustrated inFIG. 5. The first wire is stretched to trace 108B, where it is bondedand terminated.

Recall that in the prior art, a bridge was mounted above a first set offingers. To form a crossover connection, a bond wire was extendedbetween a bond pad and the bridge and was intermediately bonded to thebridge. The bond wire was then extended from the bridge to a finger of asecond set of fingers. In this manner, the bond wire was crossed overfingers of the first set of fingers. However, providing and attachingsuch a bridge was relatively labor-intensive and complex and thussignificantly added to the cost of the integrated circuit package.

Advantageously, jumper pads 702 are formed during the normal processingof substrate 102A, e.g., during the formation of traces 108. Sincejumper pads 702 are formed during the normal processing of substrate102A, there are no additional procedures or materials required forjumper pad 702. Accordingly, there is essentially no cost associatedwith jumper pads 702.

Further, long wires 110-2, including upper and lower long wires 110-2U,110-2L are formed using standard packaging equipment, i.e., standardwire bonders. By using standard packaging equipment, large tooling,capital equipment, and training costs, which would otherwise be incurredwith nonstandard packaging equipment, are avoided. As a result, package100E is fabricated at a lower cost than a prior art package having acrossover connection. Although upper long wire 110-2U crosses over asingle long wire 110, i.e., over lower long wire 110-2L, in light ofthis disclosure, those of skill in the art will understand that upperlong wire 110-2U crosses over more than one long wire 110, i.e., over aplurality of long wires 110, in other embodiments.

FIG. 8B is a cross-section view of package 100E along the line VIII-VIIIof FIG. 7 in accordance with another embodiment of the presentinvention. The embodiment of FIG. 8B is substantially similar to theembodiment of FIG. 8A and only the relevant differences are discussedbelow.

Referring now to FIG. 8B, upper long wire 110-2UA includes loopedportion 208B, a crossover portion 704A, and surface runner portion 210B.In accordance with this embodiment, crossover portion 704A is anelectrically conductive trace on an upper surface 204U of principalsubstrate 204. Crossover portion 704A electrically connects jumper pad702A to jumper pad 702B, which are formed on crossover portion 704A.Illustratively, crossover portion 704A is formed during the normalprocessing of substrate 102B, e.g., during the formation of traces 108.

Insulating layer 206A covers crossover portion 704A between jumper pad702A and jumper pad 702B. By covering crossover portion 704A, insulatinglayer 206A is located between crossover portion 704A and lower long wire110-2L and thus electrically isolates crossover portion 704A from lowerlong wire 110-2L. More particularly, crossover portion 704A passes underlower long wire 110-2L, which rests on insulating layer 206A.

Although crossover portion 704A passes under lower long wire 110-2L,upper long wire 110-2UA is said to cross over lower long wire 110-2L.Further, although upper long wire 110-2UA crosses over a single longwire 110, i.e., over lower long wire 110-2L, in light of thisdisclosure, those of skill in the art will understand that upper longwire 110-2UA crosses over more than one long wire 110, i.e., over aplurality of long wires 110, in other embodiments.

This application is related to Glenn, co-filed and commonly assignedU.S. patent application Ser. No. 09/565,887 entitled “LONG WIRE ICPACKAGE”, which is herein incorporated by reference in its entirety.

The drawings and the forgoing description gave examples of the presentinvention. The scope of the present invention, however, is by no meanslimited by these specific examples. Numerous variations, whetherexplicitly given in the specification or not, such as differences instructure, dimension, and use of material, are possible. The scope ofthe invention is at least as broad as given by the following claims.

I claim:
 1. A method comprising: forming a first trace and anintermediate bonding pad on a first surface of a substrate; attaching anelectronic component to said first surface of said substrate, saidelectronic component having a first bond pad thereon; and electricallyconnecting said first bond pad to said first trace by a first bond wire,said first bond wire being attached to said intermediate bonding pad,said electrically connecting comprising stretching said first bond wireflat along said first surface of said substrate from said intermediatebonding pad to said first trace.
 2. The method of claim 1 wherein saidfirst bond wire comprises a first wire and a second wire, saidelectrically connecting further comprising attaching said first wire tosaid first bond pad and stretching said first wire from said first bondpad to said intermediate bonding pad.
 3. The method of claim 2 furthercomprising terminating said first wire at said intermediate bonding pad.4. A method comprising: forming a first trace and an intermediatebonding pad on a first surface of a substrate; attaching an electroniccomponent to said first surface of said substrate, said electroniccomponent having a first bond pad thereon; attaching a first wire tosaid first bond pad and stretching said first wire from said first bondpad to said intermediate bonding pad; terminating said first wire atsaid intermediate bonding pad; and attaching a second wire to saidintermediate bonding pad and stretching said second wire flat along saidfirst surface of said substrate to said first trace.
 5. The method ofclaim 4 wherein said second wire is attached to said intermediatebonding pad directly on top of said first wire.
 6. The method of claim 4further comprising terminating said second wire at said first trace. 7.The method of claim 1 wherein said first bond wire is a single integralwire.
 8. The method of claim 7 wherein said electrically connectingcomprises: attaching said single integral wire to said first bond pad;stretching said single integral wire from said first bond pad to saidintermediate bonding pad; and stitching said single integral wire tosaid intermediate bonding pad.
 9. A method comprising: forming a firsttrace and an intermediate bonding pad on a first surface of a substrate;attaching an electronic component to said first surface of saidsubstrate, said electronic component having a first bond pad thereon;attaching a single integral wire to said first bond pad; stretching saidsingle integral wire from said first bond pad to said intermediatebonding pad; stitching said single integral wire to said intermediatebonding pad; and stretching said single integral wire flat along saidfirst surface of said substrate from said intermediate bonding pad tosaid first trace.
 10. The method of claim 1 wherein said forming a firsttrace and an intermediate bonding pad on a first surface of a substratefurther comprises forming a second trace on said first surface of saidsubstrate.
 11. A method comprising: forming a first trace, a secondtrace and an intermediate bonding pad on a first surface of a substrate;attaching an electronic component to said first surface of saidsubstrate, said electronic component having a first bond pad and asecond bond pad thereon; electrically connecting said first bond pad tosaid first trace by a first bond wire, said first bond wire beingattached to said intermediate bonding pad; and electrically connectingsaid second bond pad to said second trace by a second bond wire, saidsecond bond wire crossing over said first bond wire.
 12. The method ofclaim 11 wherein said forming a first trace, a second trace and anintermediate bonding pad on said first surface of said substrate furthercomprises forming a first jumper pad and a second jumper pad on saidfirst surface of said substrate, said electrically connecting saidsecond bond pad to said second trace by a second bond wire comprisingattaching said second bond wire to said first jumper pad and said secondjumper pad.
 13. The method of claim 12 wherein said second bond wirecomprises a crossover portion between said first jumper pad and saidsecond jumper pad.
 14. The method of claim 13 wherein said crossoverportion is arched over said first bond wire.
 15. A method comprising:forming a first trace, a second trace and an intermediate bonding pad ona first surface of a substrate; attaching an electronic component tosaid first surface of said substrate, said electronic component having afirst bond pad and a second bond pad thereon; electrically connectingsaid first bond pad to said first trace by a first bond wire, said firstbond wire being attached to said intermediate bonding pad; andelectrically connecting said second bond pad to said second trace usinga crossover portion extending under said first bond wire.
 16. The methodof claim 15 wherein said crossover portion extends between andelectrically connects a first jumper pad and a second jumper pad on saidcrossover portion, said electrically connecting said second bond pad tosaid second trace comprising electrically connecting said second bondpad to said first jumper pad and said second jumper pad to said secondtrace.
 17. The method of claim 1 further comprising encapsulating saidfirst trace, said intermediate bonding pad, said electronic component,said first bond pad and said first bond wire in an encapsulant to form apackage body.
 18. The method of claim 1 wherein said first bond wirecomprises a portion extending along said first surface of said substratebetween said intermediate bonding pad and said first trace, said methodfurther comprising anchoring said portion of said first bond wire tosaid first surface of said substrate.
 19. The method of claim 18 whereinsaid anchoring comprises dispensing a bead of adhesive over said portionof said first bond wire.
 20. The method of claim 18 wherein saidanchoring comprises encasing said portion of said first bond wire in asealing layer.
 21. A method of forming a package comprising: forming anintermediate bonding pad on a first surface of a substrate; attaching anelectronic component to said first surface of said substrate, saidelectronic component comprising a first bond pad thereon; electricallyconnecting said first bond pad to said intermediate bonding pad; andstretching a bond wire in contact with and flat along said first surfaceof said substrate from said intermediate bonding pad to a first trace.22. A method of forming a package comprising: forming a first jumper padand a second jumper pad on a first surface of a substrate; attaching anelectronic component to said first surface of said substrate, saidelectronic component comprising a first bond pad and a second bond padthereon; electrically connecting said first bond pad to a first tracewith a first bond wire; and electrically connecting said second bond padto a second trace with a second bond wire comprising attaching saidsecond bond wire to said first jumper pad and looping said second bondwire over said first bond wire and to said second jumper pad.